math help

What is 100/72 + 4/8?

What is 100/72 + 4/8?

This is how you add

100
72
+
4
8

Step 1

Our denominators (bottom numbers) don't match, so we can't add yet.

Since 8 is evenly divided by 72, we can multiply just one term to get a common denominator.

Multiply 4 by 9, and get 36, then we multiply 8 by 9 and get 72.

4/8 times 9

So now our fractions look like this:

100
72
+
36
72

Step 2

Since our denominators match, we can add the numerators.

100 + 36 = 136

So the answer is:

136
72

Step 3

Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction?

To find out, we try dividing it by 2...

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

136
72
÷ 2 =
68
36

Now, try the same number again.

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

68
36
÷ 2 =
34
18

Now, try the same number again.

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

34
18
÷ 2 =
17
9

Now, try the same number again.

Nope. Try the next prime number, 3...

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

No good. 11 is larger than 9. So we're done reducing.

Congratulations! Here's your final answer to 100/72 + 4/8

100
72
+
4
8
=
17
9
© 2014 Randy Tayler